A scientist's aim in a discussion with his colleagues is not to persuade, but to clarify.

Don't lie if you don't have to.

I have been asked whether I would agree that the tragedy of the scientist is that he is able to bring about great advances in our knowledge, which mankind may then proceed to use for purposes of destruction. My answer is that this is not the tragedy of the scientist; it is the tragedy of mankind.

When a scientist says something, his colleagues must ask themselves only whether it is true. When a politician says something, his colleagues must first of all ask, 'Why does he say it?

We turned the switch, saw the flashes, watched for ten minutes, then switched everything off and went home. That night I knew the world was headed for sorrow.

I am thinking of keeping a diary, not with the intend to publish it, merely to record the facts for the information of God, in case God does not know my version of the facts.

If the thickness is larger than the critical value I can produce an explosion.